After joining East Fife as player manager he led them to victory in the Scottish Qualifying Cup Final in 1920-21.
On 9 October 1948, after a mediocre start to the 1948–49 season McLean combined three young forwards, Jimmy Wardhaugh, Willie Bauld and Alfie Conn Sr., for the first time.
However, after a single appearance at right-half in a 1–0 home defeat by Dundee, Walker retired to concentrate fully on learning the managerial ropes.
[8][6][4] McLean's death on 14 February 1951 saw Walker promoted to the position of manager; his reign was to prove the most successful period in the club's history.
[9] Walker was always quick to acknowledge the contribution made by McLean and his fatherly interest in the welfare and development of the players.